Are yyou saying the Hyuga were poorly done in general (compared to Akatsuki, other clans, kage) or only compared to the major clans of Uzumaki, Senju and Uchiha?
Only compared to the rest of the Otsutsuki clans.
I think the other clans, kages, Akatsukis were abandoned as well when the plot moved towards the Rikudou Senin and the entire thing moved towards completely going to Sasuke and Naruto only in terms of power scaling and development (and through association the Uchiha and Senju and Hagoromo's lineage in general)
Certainly the Hyugas were the main focus for Part 1 Naruto but as they moved forward to the whole Tailed Beasts and capturing Sasuke, the focus on Hyugas were left until they were touched up again later on in Part 2, Shippuden. Even still, it was only to scale everyone else to the current progression of our heroes (the story still does not make Naruto and Sasuke a pure focus but rather the Akatsuki, etc.)
And the reason Senju, Uchiha and Uzumaki were so powerful ultimately comes down to pure plot device - ancestral warfare - which doesn't apply to the Hyuga
Well, that's the thing: It does. Part of why Hyugas felt underdeveloped is due to the Hyuga being part of the Otsutsuki Clan.
The Uzumaki weren't involved too as we already know that they were annihilated and only Naruto was ever involved in the transmigrant wars due to the Senju not having any vessel.
You may argue about Nagato's involvement but the main reason for that is due to Madara picking him for his chakra and life force: Being part Senju and part Uzumaki. He is not a transmigrant himself. Merely a tool of it.
So really, the very reason for all this is explained as being an exception even among the elite clans, so the Hyuga hype isn't disrespected or side lined
They were side lined. Which is why we got The Last movie to get more idea of what the Hamura's side were like: The main family (which is undoubtedly where Hyugas were from) and the branch family (where Toneri is a complete copy of Naruto's Uzumaki powers, hence why I hypothesize that the Uzumaki is from Hamura's side).
With that said, whether or not the Hyugas are instrumental on the transmigrant wars is irrelevant. The reason why they felt lackluster and underdeveloped is due to their relation to the Otsutsuki and the powers that they (the other 3 clans) have because of that lineage.
And even then, the Hyuga still got their unnecessary devlopment. Toneri and Hinata and the Tenseigan! It was totally unnecessary, yet they still got something.
That wasn't unnecessary and that wasn't even about the Hyuga. Even during that movie, the Hyuga were merely plot devices. They exist there because of their ties to Hamura and the fact that their eyes are needed for the Tenseigan.
The movie was there to provide information to connect the dots and answer the "what if"
"what if it was the Yang (branch, younger, body) that wanted to evolve instead of the Yin (main, older, eyes)?"
"who is the 4th clan? what are they like?"
"what is the equivalent of Hagoromo on Hamura's side?"
These questions were more about the branch side of Hamura's family than the Yin (which is the Hyuga) and the combination of both.
So again, they are merely sidestories again.
So the best one can say is that Hyuga development (Tenseigan) wasn't needed or relevant during Shippuden, not that it didn't happen.
This is correct as the Tenseigan was more of the transmigrant war on the moon than the one on earth. They were reflective of what was transpiring on Earth.
Yin Sage of 6P: Hagoromo of Earth
Yang Sage of 6P: Hamura of Moon
Tenseigan wasn't relevant as it is almost impossible for the Moon people to get involved at that time. The full escalation of the war on the Moon did not happen until the summoning of the Gedo Mazou by Madara and the complete resurrection of the God Tree + Kaguya.
So they had no reason to be involved with the Earth and strive for the transcendence to So6P and gain Tenseigan (I think that even that was unknown to them until they saw what Madara accomplished).
The reason for Uchiha development in Shippuden is something that doesnt apply to the Hyuga, not because of inherent superiority.
Superiority was never in question here. The issue being addressed is the Hyuga being abandoned in terms of Otsutsuki power progression.
Sasuke and Naruto were scaling in power and through that the Uchiha and Uzumaki. However, Senjus also scaled along side the Uchiha as that were the 2 clans of Hagoromo. Uzumaki only scaled through Naruto.
However, because the Hyugas weren't involved, they were never directly developed. This is the issue here as they are completely involved for the Tenseigan. Yet, no development occured. Only Toneri, which can be associated with the branch family which proved too similar to Naruto which in turn is associated to the Uzumaki. Therefore, The Last movie solely focused on Naruto and Toneri and Hamura and the branch family.